Apparatus for producing stripper wells



July 22, 1958 I J. D. LEONARD 2,

APPARATUS FOR PRODUCING STRIPPER'WELLS Filed Nov. :5, 1954 3 Sheets-Sheet 1 INVENTOR. Jesse 0. Leonard July 22, 1958 v J. D. LEONARD 2,844,029

APPARATUS FOR PRODUCING STRIPPER WELLS Filed Nov. 3, 1954 3 Sheets-Sheet 2 FIG. 2

INVEN TOR. Jesse I). Leonard July 22, 1958 J. D; LEONARD 2,844,029

APPARATUS FOR PRODUCING STRIPPER WELLS Filed Nov. 3, 1954 5 Sheets-Sheet I5 INVEN TOR. Jena 0. Leonard United States PatentfO 2,844,029; APPAI IA TUS FOR PRODUCING STREPER WELLS V JesseD. Leonardg Big Spring, Tex.

Application-November 3, 1954, Serial No; 466,636

1 Claim. (Cl. 73-200).

'Ihis invention relates to an apparatus for -determin ing;the--most effective pumping procedures for -stripper wells.

. It hasqbeen the practice in the past when the rateof seepage 'intovan oil well falls below the rate at which the well pump can emptythe well; that is whenthe well isclassified as a stripper well, to pump the well for only, short periods of the dayfallowin'gnon-pumping perriods; for the seepage to fill the well so that the we1l pump can operate at capacity while in use.

Upjtot this time, however, it has been diflicult to determine how many periods a day the well should bepumped and how long eachpumpingperiod should be in order that-therwell' could be pumped mosteificiently.

Inthe -past,-w-henitwas-desired to obtain full apro ductivity from a stripper well, a guess was made-at thenumber of pumping periods and their duration to. be usedrandthis guesswas usually far too high sothat the welltpumps were often in operatiomusing upflfuel without. producing any oil from the well. I t

It is the principal object of the present invention to provide an apparatus for determining the most eflicient pumping procedures for. stripper wells.

It is a further object of this invention to provide a device for measuring the, output of oil wells which. will. be substantially unaifected by the corrosive materials which it"measures;

It isia' further object of this invention to provide a device that will indicate on a time chart when. and how much oil a well produces.

Itis-a-further object of thisinvention to combine with this measuring apparatus a device for periodicallysampling the output of the well.

Further objects and advantages of my invention will appear in the following specification which describes a sp'ecifi'cprocedure and apparatus for the practice of my invention.

Broadly stated, the apparatus for my invention con sists of a device for measuring the output of stripper wells whichare not sufliciently productive to-permit-continuous productive pumping which comprises in combination-c (a) Means for forming a continuous time record which shows the duration of the alternate pumping-andidle periods of the well, and

(b) Means for additionally indicating'on'those por-f tions of said record which representlthe pumping periods, the times at which the pumping operationcom ple'tes the delivery of successive equal predetermined quantities of oil.

In the accompanying drawings, Fig. 1 is a schematic flow diagram of one form of apparatus constructed in accordance with theprinciples of my invention.

2,844,029 Patented July 22, 1958 Fig. 2i-is'a wiring diagram of :the electri'calxcontrol ling. and: recording circuit used: in: conjunction withtthisa from the well into' a pipe lwhich. serves as 'the'intakei conduit for the apparatus of 'my invention. The: conr-: bination'iof'oilandzgas is delivered by the intake conduit 1, atlalevel 2 shown in the figure, to. a surge .tank 3'; where the gas separates. out andescapes through apiper 4' and a check valve 5 into a.flow line:6.1 The oil= flows from" the surge' tank 3 through a pipe 7-containing iar check valve 8, through the lower part of a pipe 9, through.

a centrifugal; pump 10 111 the direction opposite :thedirection'of fluid delivery of the pump, through a pipe" 111 into a tankiof'known volume12.v As the oil first starts: to fill the tank '12, it'closes a float'switch 1'3 (Mercoid LiquidLevel ControlType 123). The oil continues fill-' ing'the tank "12 until'it closes aufloatI switch'.14*(Mer-: coid Type 123);

Connectedto-thev intake pipe 1 is a'pipe .15 which :extends from the center of the pipe 1 to a three-way. mag-r netic valve 16. Connected tothebottom ofxthe valve. 16" is. 'a'sample receiver '17 which contains an outlet'valv'e 43." Connecting'the top' of the valve 16"to:the toprof the surge t'ank'la'is a pressureequalizing pipe 18, and con meeting, the top of thesample receiver. 17 tothe'top ofthesurge tank' 3is a pressure equalizing pipe 19. The pipes'1'5,n18,' and 19each contain 'a'valve '20-'which' is" normally open.

When the tank of known volume 12is being filled,

thethree-way magnetic valve 16*(Mercoid-type" K-13;

3-Way packless magnetic valve) connects the pipes 155 and-18, and fluid from the pipe-1 risesin the pipe-18 to the level-2.-

Whenthe float switch .14 is closed, the magnetic-valve:

16 connects thepipe 18 to. the sample receiver- 17 and. the fluid in the-pipe 18 flowsdown into the sample re ceiver 17.

When-the float switch 14 is closed the centrifugalpumpr 10' is automaticallystarted to empty the tank 12. A-pressure equalizing pipe 44'connects the tops of the surge tank 3 and the tank 12 so that the tank 12 can be freely.

filled and emptied. When the centrifugal pump 10 is started the check valve 8 closes and a check valve 21" in the top part of thepipe 9 opens sov that the oil .in the.

tank 12 is forced out into the flow line 6.

When the tank 12 is emptied the float switch 13opens so that the magnetic valve 16 again connects thepipes 15 and 18 and the centrifugal pump 10 stops running; When the pump 10 stops running, the check valve-21" closes; and the check valve 8 opens. The cycle is then repeated.

Every time a cycle of the above description is completed a volume of oil, equal to the volume ofthe tank of known volume 12, is pumped into the flow line'6.

tively of the centrifugal pump motor 10. switches 31a are apart of the overload relay and this:

overload relay is used to protect the motor from being b'urnedout in case of overload or from other abnormal:

conditions such as low voltage or low voltage on one phase. All of the switches, etc., shown inside the dotted square are a part of a 3-phase magnetic starter which is a conventional item. Switches 31a are a part of this motor starter. Connected in series between the leads 22 and 23 are the float switch 13, a manual stop switch 29, a magnetic energizing unit 30, and a parallel combination of the float switch 14, a manual start switch 31, and a hold switch 32. Also connected across the leads 22 and 23 is a control transformer 33, to which is attached in series a resistor 34 and a twenty-four-hour clock driven spring wound recorder 35. The resistor 34 and the resistance of the recorder 35 are so related that when the resistor 34 is shorted out the recorder deflection will move from scale to full scale. Connected across the terminals 26 and 27 of the pump motor is a two-pole relay 36 which, when energized, shorts out the resistor 34 and operates the three-way magnetic valve 16.

When the pumping unit motor is stopped, the recorder 35 registers a zero deflection; the switches 13 and 14 may be open or closed; switches 25, 31 and 32 are open; the switch 29 is closed; the two-pole relay 36 is open; and the three-way magnetic valve 16 connects the pipes and 18.

When the pumping unit motor is started the leads 22,

23, and 24 are energized, and, with the resistor 34 in series with the recorder 35, the recorder registers scale deflection. As the pumping unit delivers oil to the surge tank 3, oil flows into the tank of known volume 12 and closes the float switch 13. As the tank 12 is being filled, the recorder 35 continues to register a /1, scale trace on the time chart. When the tank 12 is filled, the float switch 14 closes so that the magnetic energizing unit operates to close the switches 25, starting the centrifugal pump motor 10 and energizing the relay 36. As the relay is closed, the resistor 34 is shorted out, and the recorder trace moves to full scale deflection. Also, when the relay 36 is closed,

the magnetic valve 16 changes, sealing off the pipe 15, and

connecting the pipe 18 to the sample receiver 17. As the pump 10 begins to empty the tank 12, the float switch 14 opens, but the hold switch 32 keeps the circuit closed. The recorder continues to trace a full scale deflection until the pump 10 empties the tank 12 and the float switch 13 opens. When the float switch 13 opens, the magnetic energizing unit 30 opens, stopping the centrifugal pump 10, returning the trace of recorder 35 to scale deflec tion, and changing the three-way magnetic valve 16 to seal the sample receiver 17 and connect the pipes 15 and 18. The recorder continues to trace a scale deflection on the time chart until the pump 10 is again started. The manual start switch 31 is provided in the circuit so that the tank 12 can be emptied of any oil it contains before it is moved to a new location. The manual stop switch 29 is provided to stop the centrifugal pump if it should become necessary.

In experiments in which I have used my invention, I have also employed a similar electric circuit containing a two-circuit recorder shown as 37 in Fig. 3. One circuit of the recorder 37 is connected directly to the lines 22 and 23. The other circuit is connected to lines 26 and 27 to be energized at the same time with centrifugal pump 10. One circuit records when the well pumping unit motor is operated and the other records when the pump motor 10 is operated.

For the purpose of making my apparatus more easily operable on wells of different outputs, I have provided a partition 38 dividing the tank 12 into two equal parts of known volume, a pressure equalizing pipe 39 connecting the tops of the two halves, and a manual valve 40 in the pipe 11 which can be used to close oif one half of the tank. In the apparatus shown I have provided two glass liquid level gauges 41 and 42 on the sides of the tanks 3 and 12 respectively so that the quantities of oil in the tanks can be easily noted. The valves 20 in the pipes 15, 18 and 19 are provided so that the sampling unit can be closed off by closing them.

During each day that the apparatus of my invention is used, it records the following data:

( 1) The time when each pumping period is started,

(2) The time when the centrifugal pump delivers each unit volume of oil, and

(3) The time when each pumping period is stopped.

DETERMINATION OF THE NUMBER OF PUMPING PERIODS TO BE USED The number of pumping periods used each day in producing a stripper well is important for two reasons:

(1) The rate of flow of oil into a stripper Well is a function of the amount'of oil already in or near the well hole, frequent pumping of the well is advantageous so that oil will flow into the well faster and hence the well will produce more.

(2) Since fuel is dissipated somewhat faster when the Well pumping unit is being started than when it is in steady operation, it may be desirable to minimize the number of pumping periods used. During cold weather, however, when the oil in the gear case and flow lines is stifi or when the well must be pumped several minutes before any fluid flows, it is desirable to maintain the number of pumping periods to a minimum provided production is not sacrificed or the total amount of power used is not increased excessively thereby.

It is therefore advantageous to find the smallest number of pumping periods which will still yield substantially full production from the well. This can be found as follows:

By utilizing pumping periods which substantially exhaust the well, first pump one period a day, then two equally spaced periods, then three equal periods, etc., noting for each day tested, the total output of the well. Continue increasing the number of pumping periods per day until the total output per day levels off, then operate the well at the smallest number of pumping periods per day that yields substantially full production from the well. This practice may be reversed by starting with a large number of periods per day and then reducing the pumping periods.

DETERMINING THE PRODUCTIVE DURATION OF A PUMPING PERIOD The time from the beginning of each pumping period to the time the centrifugal pump has discharged its last unit volume of oil for thatperiod is the productive duration of the pumping period. When my apparatus is used, this duration is measured on the time chart and thereafter used as the duration of the pumping period, thus eliminating the unproductive time at the end of the pumping period.

In one experiment I performed on a stripper well wherein I attempted merely to shorten the operating time of the well pumping unit, I ran three twenty-fourhour tests, the results of which are shown below:

Test 1 Number Pumping Time of DuIn s Bbl.

at 36 Bbl Eae The time chart from the test indicated that the well was productive for only a short portion of each pumping period. Therefore, when conducting the second test, I

reduced both the number of pumping periods and their durations.

The results of this test indicated a reduction of pumping time from 281 minutes to 105 minutes per day with no reduction in total well output. However, the time chart indicated that there was still a substantial portion of each pumping period that was unproductive. Therefore, for my final test, I further reduced the duration of each period.

Test 3 Number Pumping Time of Dump Bbl.

at Bbl. Each Min. 7:55 a. m. to 8:16 a. n1 21 3 1% 3:45 p. m. to 4:13 p. m 28 4 2 11:47 1). m. to 12:15 a. 1n 28 4 2 Total 77 11 5% The results of the test indicated that the total pumping time could be reduced to 77 minutes per day without lowering the total well output. The time chart in this case showed that only a small part of each pumping period was unproductive. As a result of these tests, the well continued production at the same output as before but using three pumping periods of 25 minutes each.

By the practice of my invention, I was able to reduce the pumping time of this particular well by more than 70 percent without noticeably afiecting the total well output.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in the following claim or the equivalent of such be employed.

I therefore particularly point out and distinctly claim as my invention:

A device for measuring the oil output of an oil well having an oil pumping unit associated with said oil well comprising a conduit connected to the output end of said pumping unit, a surge tank into which said conduit empties, means for withdrawing gaseous fluid from said surge tank, a second tank having a known capacity, a second conduit connecting said surge tank and said second tank, a pump in said second conduit between said surge tank and said second tank disposed to empty said second tank, a check valve in said second conduit between said surge tank and said pump in fluid communication with said pump and disposed in open position in a direction of flow towards said pump, a float switch secured at the top of said second tank in fluid communication with the interior of said tank and connected with said pump to start said pump, an output conduit in fluid communication with said second conduit and said pump, a check valve in said output conduit in open position in a direction of flow away from said pump, a second float switch connected to said pump and in fluid communication with said second tank to stop said pump when said second tank is empty and means for recording the times and duration of operation of said pumping unit and for continuously recording on a time chart when and how many times said second tank is emptied.

References Cited in the file of this patent UNITED STATES PATENTS 749,390 Lowe Jan. 12, 1904 1,130,792 Burton Mar. 9, 1915 1,911,777 Taylor May 30, 1933 2,404,132 Hayward July 16, 1946 2,494,124 Hegy Jan. 10, 1950 2,505,905 McAfee May 2, 1950 FOREIGN PATENTS 582,155 Great Britain Nov. 6, 1946 588,936 Great Britain June 6, 1947 OTHER REFERENCES Publication: The oil & Gas Journal, Oct. 17, 1935 issue, p. 32 in Engineering and Operating Section, an article by H. K. Ihrig. 

